The inside of the ankle is anatomically known as the medial side, located closest to the large bony bump called the medial malleolus. Pain in this region, whether acute or chronic, can arise from damage to ligaments, tendons, nerves, or bone structures. While this information can help you understand potential causes, it is not a substitute for a professional medical diagnosis. Because the causes of pain on the inside of the ankle can be complex, a healthcare provider should evaluate persistent or severe symptoms.
Acute Pain from Ligament Sprains
Sudden, intense pain following a traumatic event suggests an acute injury to the ligaments, which are strong bands of tissue connecting bones. While most ankle sprains involve the ligaments on the outside of the foot, a forceful outward rolling motion, known as eversion, can strain the medial ligament complex. This complex is the Deltoid ligament, a broad and strong structure that helps stabilize the ankle joint.
When this ligament is overstretched or torn, the initial symptoms are immediate, sharp pain and swelling directly over the medial malleolus. Attempting to put weight on the foot immediately after the injury can be extremely painful or impossible, which is a strong sign of significant trauma. Applying rest, ice, compression, and elevation (R.I.C.E.) can help manage the initial swelling and pain, but any severe sprain requires professional assessment to rule out an associated fracture or high-grade tear.
Chronic Pain from Tendon Problems
The most frequent cause of chronic or progressive medial ankle discomfort is a problem with the posterior tibial tendon. This tendon runs along the inner ankle, attaches to bones in the foot, and plays a crucial role in maintaining the arch during walking. Dysfunction of this tendon is often a progressive condition, beginning with inflammation and advancing to degeneration or micro-tears.
As the condition progresses, the tendon’s ability to support the foot’s arch diminishes, leading to a gradual flattening of the foot, often termed adult-acquired flatfoot. Early symptoms include pain and swelling felt directly along the course of the tendon, which typically worsens with prolonged activity such as walking or standing. Over time, the pain may eventually shift to the outside of the ankle as the foot structure collapses. This change in foot alignment makes it difficult to perform a single-leg heel raise, a common test used to assess the tendon’s function.
Pain Caused by Nerve and Bone Conditions
Less common but important sources of medial ankle pain involve nerve compression and structural changes in the bone. Tarsal Tunnel Syndrome (TTS) is a condition where the tibial nerve, which passes through a confined space on the inside of the ankle, becomes compressed. The symptoms are distinctly neurological, often described as burning, tingling, numbness, or shooting pain that radiates into the sole of the foot. These sensations often become more pronounced at night or after extended periods of standing.
Structural bone issues like medial ankle osteoarthritis (OA) or a stress fracture can also cause pain in this area. Ankle OA occurs when the cartilage cushioning the joint wears down, often resulting from a past injury or fracture. This deep, aching joint pain often results in stiffness, especially in the morning, and can produce a grinding or popping sensation during movement.
A stress fracture of the medial malleolus, the bony prominence on the inside of the ankle, is a tiny crack that develops over time due to repetitive, excessive loading. Pain from a stress fracture typically increases with weight-bearing activity and is intensely tender when pressure is applied directly to the specific bony spot.
Knowing When to Seek Professional Help
Immediate medical attention is necessary if you experience a visible deformity of the ankle or foot, or if a sudden injury prevents you from putting any weight on the affected foot. A medical professional should also evaluate any pain accompanied by a fever, chills, or spreading redness, as this could signal an infection.
Schedule an appointment if your pain and swelling do not begin to improve after 48 to 72 hours of rest and self-care measures. Chronic pain that persists for several weeks, or pain that progressively worsens despite attempts to reduce activity, requires an accurate diagnosis. A healthcare provider can use a physical exam and potentially imaging studies to differentiate between ligament, tendon, nerve, and bone problems, ensuring the most effective treatment plan is started.